Plant Tissues Research Articles

Use of Vetevera Grass (Chrysopogon zizanioides) in a Constructed Wetland to Remove Heavy Metals from Kege Wet Coffee Processing Plant, Dale Woreda, Sidama Regional State, Ethiopia

Conventional methods for removing heavy metals from contaminated water are prohibitively expensive and, more significantly, ineffective, especially when the concentration of heavy metals is low. This paper evaluated the use of vetevera grass in a constructed wetland to remove Ca, Cd, Co, Cu, Cr, Fe, K, Mn, Na, Pb, and Zn metals from Kege Wet Coffee Processing Plant, Dale Woreda, Sidama Regional State, Ethiopia using a two vertical flows constructed wetland of 132 square meters in size with Eleven meters in length and 12 meters wide. The 11m * 3m * 1m open space between two constructed wetlands is developed. The second wetland was built, and it serves the same purpose as the previous one but discharges water into the river. The construction of the wetland is performed by digging 20 cm wide, and 30 cm apart furrows. vetiveria grasses was planted at 20 cm intervals. Heavy metals (Ca, Cd, Co, Cu, Cr, Fe, K, Mn, Na, Pb, and Zn) were measured from soil and plant samples from the inlet to the outlet sampling sites using standard procedures from two compartments (soil, and macrophytes) of constructed wetland. Findings indicated that Ca (460.0 ppm) had the highest mean concentration of heavy metals, whereas Ni (0.50 ppm) had the lowest in the soil sample. Metal absorption by vetiver grass is the highest concentration found in plant tissues grown in the following order k > Ca > Na > Mn > Fe > Zn > Cu >Ni >Cr in shoots. The order of the heavy metal contents in the roots of vetiver grass was k > Ca > Na > Mn > Fe > Zn > Cu >Ni >Cr. The plant was found to be effective at transferring Mn and Ni from the roots to the shoots based on translocation and bioconcentration, whereas it served as a potential phytostabilizer for Ca, Cu, Cr, Fe, K, Na, and Zn since the TF values are lower than 1, which show that vetiver grass prefers to accumulate heavy metals in the roots rather than the shoot and so supports its potential for phytostabilization. From the present study, it was evident that vetiver grass is an ideal candidate for wastewater treatment using constructed wetland technology.

Plant Tissues as Biomonitoring Tools for Environmental Contaminants

Environmental toxins pose significant threats to ecosystems and human health. Monitoring and assessing these toxins are crucial for effective environmental management and public health protection. Recently, plant species have garnered increasing attention as potential bioindicators for identifying and evaluating ecological toxins. Since plants often come into touch with harmful compounds in soil, water, and the atmosphere, they are particularly valuable for analyzing how human activities influence the terrestrial ecosystem, the aquatic system, and the atmosphere. This review paper emphasizes using plant species as a resource for tracking environmental pollution and analyzing contaminants. We focused on plants because they are significant indicators of soil, water, and air quality changes. Many plants have been used as bio-indicators to assess and predict pollution, toxicity, and environmental changes. These include Allium cepa, Vicia faba, Pisum sativum, Zea mays, Nicotiana tabacum, lichens, and mosses. The idea of bioindicators is discussed in the current paper, with a focus on plants as possible candidates for bioindicators for toxin assessment and related outcomes.

Hesperidin as a Species-Specific Modifier of Aphid Behavior.

Hesperidin is a highly bioactive natural flavonoid whose role in ecological interactions is poorly known. In particular, the effects of hesperidin on herbivores are rarely reported. Flavonoids have been considered as prospective biopesticides; therefore, the aim of the present study was to examine the influence of hesperidin on the host plant selection behavior of three aphid (Hemiptera: Aphididae) species: Acyrthosiphon pisum Harrris, Rhopalosiphum padi (L.), and Myzus persicae (Sulz.). The aphid host plants were treated with 0.1% and 0.5% ethanolic solutions of hesperidin. Aphid probing behavior in the no-choice experiment was monitored using electropenetrography and aphid settling on plants in the choice experiment was recorded. The results demonstrated that hesperidin can be applied as a pre-ingestive, ingestive, and post-ingestive deterrent against A. pisum, as an ingestive deterrent against R. padi, and as a post-ingestive deterrent against M. persicae using the relatively low 0.1% concentration. While in A. pisum the deterrent effects of hesperidin were manifested as early as during aphid probing in peripheral plant tissues, in M. persicae, the avoidance of plants was probably the consequence of consuming the hesperidin-containing phloem sap.

INCREASING SOME FLAVONOIDS COMPOUNDS FOR ECHINACEA PURPUREA L. USING COPPER OXIDE NANOPARTICLES IN VITRO.

This study was aimed to increase some flavonoids active compounds production in Echinacea purpurea seedlings through plant seeds treatment with different concentrations of copper oxide nanoparticles that daignosed and characterized using AFM technique. This research was implemented at plant tissue culture labrotary of College of biotechnology - Al Nahrain University, during the period of 2021 and 2023. The experiment designed factorial within CRD using three factors and ten replicates (3X3). Sodium hypochlorite concentration (S1, S2, S3, S4) (0.0, 1, 2, 3%) represented the first factor, treatment duartion time (T1, T2, T3) (5, 10, 15min) represented the second factor and copper oxide nanoparticles concentrations (C1, C2, C3, C4) (0.0, 25, 50, 75mg/ml) represented the third factor. Results showed that the full reduction in the contamination rate of the selected E. purpurea explant recorded in 3% sodium hypochlorite at 10 and 15min. The results also showed that there were a significant increase in the shoots numbers in 50mg/ml CuNPs that recording the highest shoots numbers, the shoot length increased significantly within the 25mg/ml recording 13.5cm then decreased in 50 and 75 mg/ml and the seedlings dry weight increased significantly up to 50mg/ml CuNPs that recording the highest seddlings dry weight, then the seedlings dry weight also decreased significantly in 75mg/ml CuNPs. Also, all the analyzed flavonoids compounds using HPLC device as Echinolone, Humulene, Coumarin, Myricetin, Heperidin and Naringin concentrations were significantly increased in 50 and 75 mg/L-1 Cu ONPs, except the Humulene and Coumarin compound that significantly decreased in 75 mg/L-1 Cu ONPs in comparsion to the control.

EFFECT OF DIFFERENT LEVELS OF SALT AND DROUGHT STRESSES ON GENE EXPRESSION OF TWO TOLERANCE-DIFFERENT TOMATO CULTIVARS IN VITRO

A lab experiment was conducted at the Plant Tissue Culture Lab / College of Agricultural Engineering Sciences / University of Baghdad. This experiment was aimed to investigate gene expression index in tomato (Solanum lycopersicum L.) after preparation of salt and simulated drought stresses. Two tomato cultivars were selected which claimed to exhibit different levels of tolerance toward abiotic stresses designated as salt-tolerant Yassamine (Y) and salt-sensitive GS12 (G) to assess the test. Seven day-old seedlings from both cultivars were grown in MS media supplemented with four concentrations of NaCl at 0, 50, 100 and 150 mM and four concentrations of PEG at 0, 10, 20, and 30% for 48 hours. The results were showed that Y cultivar exhibited more proline secretion and chlorophyll content when compared with G. In addition, Y cultivar showed less ion leakage and less affected by elevated abiotic stresses in term of seedling weight variation when compared to G counterparts. The SDS-PAGE gel analysis showed that Y cultivar showed more band intensity when compared with G suggested more corresponding gene expression of tolerant protein against abiotic stresses.

Nitrogen-Rich Sewage Sludge Mineralized Quickly, Improving Lettuce Nutrition and Yield, with Reduced Risk of Heavy Metal Contamination of Soil and Plant Tissues

Sewage sludge should primarily find use in agriculture, reducing the quantity directed towards alternative disposal methods like incineration or deposition in municipal landfills. This study evaluated the agronomic value and the risk of soil and plant tissue contamination with heavy metals in sewage sludge obtained from two wastewater treatment plants (WWTP). The experiment was arranged as a 2 × 5 factorial (two sewage sludges, five sanitation treatments), involving lettuce cultivation in pots over two growing cycles. The two sewage sludges were sourced from the WWTPs of Gelfa and Viana do Castelo and underwent five sanitation and stabilization treatments (40% and 20% calcium oxide, 40% and 20% calcium hydroxide, and untreated sewage sludge). The Gelfa sewage sludge, characterized by a higher initial nitrogen (N) concentration, resulted in greater dry-matter yield (DMY) (12.4 and 8.6 g plant−1 for the first and second growing cycles, respectively) compared to that from Viana do Castelo (11.0 and 8.1 g plant−1), with N release likely being a major factor influencing crop productivity. The high N concentration and the low carbon (C)/N ratio of sewage sludge led to rapid mineralization of the organic substrate, which additionally led to a higher release of other important nutrients, such as phosphorus (P) and boron (B), making them available for plant uptake. Alkalizing treatments further stimulated sewage sludge mineralization, increasing soil pH and exchangeable calcium (Ca), thereby enhancing Ca availability for plants, and indicating a preference for use in acidic soils. Cationic micronutrients were minimally affected by the sewage sludge and their treatments. The concentrations of heavy metals in the sewage sludge, soils, and lettuce tissues were all below internationally established threshold limits. This study highlighted the high fertilizing value of these sewage sludges, supplying N, P, and B to plants, while demonstrating a low risk of environmental contamination with heavy metals. Nevertheless, the safe use of sewage sludge by farmers depends on monitoring other risks, such as toxic organic compounds, which were not evaluated in this study.

Optimization of Sterilization Parameters for Isolation of Endophytes from Allium sativum and Exploring its Antibacterial Activity

Endophytic bacteria reside within the plant cell and are beneficial to it in a number of ways like growth, protection to environmental conditions and sustainability in favor of the hosts. Throughout the ages, Garlic (Allium sativum L.) has legendary therapeutic importance. The important step in endophyte isolation is the removal of plant tissue surface microflora, called as surface sterilization. Endophytes from medicinal plants may mimic the compound produced by the host plant and also plays an important role in production of bioactive compound, so it is necessary to isolate endophytes, not the epiphytic microbes. The present investigation was undertaken with an aim to optimize the sterilization parameters viz: time and concentration of ethanol and sodium hypochlorite for isolation of endophytic bacteria as well as exploring their antibacterial activity from Allium sativum. The results revealed that concentration and exposure time of sterilizing agent caused prominent surface sterilization but have negative effect on isolation of endophytes. Experimental results revealed that 70% ethanol (6 min), 2% sodium hypochlorite (1 min) followed by 70% ethanol (30 sec) is effective for surface sterilization of leaf and 70% ethanol (6 min), 3% sodium hypochlorite (1 min) followed by ethanol (30 sec) for bulb of Allium sativum. A total of 86 bacterial endophytes were recovered and screened for antibacterial activity against Enterococcus faecalis, Bacillus cereus ATCC 11778, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Enterobacter, Klebsiella pneumoniae, Salmonella typhi and Proteus. Out of 86 bacterial endophytes, only (9%) endophytes were found to be inhibiting one or all test human pathogen. The findings of the present study suggest that use of optimized sterilization conditions are effective for removing surface bacterial strains without affecting endophytes as well as the Allium sativum plant of the Jaunpur district represents an excellent reservoir of endophytic bacteria and novel source of bioactive compounds. On the other hand different concentration and time of their exposure to different parts of plant is required for proper surface sterilization of that part and isolation of endophytes.

Rapid Multiplication of Geographical Indication (GI) Tagged Mysore Mallige (Jasminum azoricum L.) Using Single Node through In vitro Culture

Aims: The present study was undertaken to rapid multiplication of (GI) tagged Mysore Mallige (Jasminum azoricum L.) using single node through in vitro culture. Study Design: The present study follow Completely Randomized Design (CRD). Place and Duration of Study: The study was conducted at the Plant Tissue Culture Laboratory, Department of Horticulture, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bengaluru, from 2020 to 21. Methodology: Single node cutting from the young shoots of field growing plants were used as explants to conduct the experiment. The explants were sterilized and placed on MS medium supplemented with different concentrations and combinations of growth regulators, namely BAP and Kinetin. Results: Among the different combinations of growth regulators, the combination of BAP 1.5 mg L-1 and Kin 1.5 mg L-1 produced maximum number of shoots from single node. Very low intensity of callus formation was observed from the cut ends of single node explants that were cultured on half strength MS medium consisting of 1.5 mg L-1 BAP + 0.0 mg L-1 Kin and 1.5 mg L-1 BAP + 1.0 mg L-1 Kin. Conclusion: The use of growth regulators such as BAP and KIN is reliable for shoot regeneration even when the field explants are used.

Development of VEGF mimetic QK peptide on polycaprolactone nanofiber for vascular tissue engineering

Electrospinning allows promoting vascular tissue formation. Polycaprolactone (PCL) is a promising polymer for vascular tissue engineering because of its great mechanical strength and efficient fabrication. However, PCL shows limited biocompatibility owing to its hydrophobic structure. PCL nanofibers can be modified by peptides to improve biological activity. KLTWQELYQLKYKGI (QK) is a peptide that mimics the Vascular Endothelial Growth Factor (VEGF) by organizing endothelial cells. It is critically important to identify the optimum concentration of QK peptide conjugation onto PCL nanofiber for vascularization. Thus, PCL nanofibers were conjugated by different QK peptide concentrations (10 µM, 100 µM and 1000 µM). QK conjugated nanofibers were characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis. The vascularization was evaluated by Live and Dead staining assay, real time PCR of platelet/endothelial cell adhesion molecule (PECAM-1), VEGF and vascular endothelial-cadherin (VE-cadherin) genes and VEGF immunofluorescence analysis. The surfaces of PCL nanofibers were modified by different concentrations of QK peptide. The roughness of nanofibers increased depending on the increased concentration of QK peptide. The higher cell attachment and cell viability were observed in 1000 µM of QK peptide. 1000 µM of QK peptide showed higher vasculogenic potential in terms of PECAM, VEGF, and VE-cadherin gene expression than all the other experimental groups. In the same on gene expression analysis by qPCR, 1000 µM concentration of QK peptide showed the higher VEGF protein than the other experimental groups. 1000 µM concentration of QK peptide can be used to improve the vasculogenic property of PCL nanofibers.

Can Arbuscular Mycorrhizal Fungi Enhance Crop Productivity and Quality in Hydroponics? A Meta-Analysis

Finding environmentally friendly solutions for crop growth and productivity has been gaining more attention recently. This meta-analysis aims to understand the combined application of arbuscular mycorrhizal fungi (AMF) and hydroponic systems compared to AMF in conventional (soil) systems. The analysis of up-to-date studies revealed that the root colonization, calculated as the proportion of colonized root segments relative to the total root length, by AMF in conventional (soil-based) culture exceeded hydroponic (or soilless) culture systems by 16.8%. The mean root colonization by AMF was determined to be 52.3% in hydroponic systems and 61.1% in conventional systems. Within hydroponic systems, the root colonization ranged from 2% to 20% after 10 days of inoculation, and notably, it exceeded 50% after 30 to 65 days, depending on the growing substrate and species. Under hydroponics, AMF application had a higher (compared to none-inoculated) positive effect on crop biomass and yield than fruit and leaf quality (antioxidants, phenols, and sugars) as well as leaf nutrients. However, AMF do not always have the potential to improve crop growth, quality and productivity in hydroponics. Among the studies analyzed in this review, approximately 34% (no effect: 29%; negative: 5%) reported no discernible positive effect on biomass or yield, 37% (no effect: 16%; negative: 21%) on fruit or leaf quality, and 60% (no effect: 47%; negative: 13%) on nutrient levels within plant tissues. To improve the performance of AMF in hydroponic systems, the meta-analysis recommended maintaining phosphorus levels in the nutrient solution within the range of 0.15 to 15.5 mg L−1 as elevated levels (40–75 mg L−1) were found to significantly reduce AMF colonization. Additionally, it was observed that certain hydroponic techniques, such as the presence of air bubbles generated by air pumps in floating hydroponic systems (Deep Flow technique) and continuous circulation of the nutrient solution (Ebb and Flow systems), may create dynamic conditions that could potentially hinder the introduction of AMF spores into hydroponic systems and potentially compromise the integrity of the spores and hyphae.

Implications of the Propagation Method for the Phytochemistry of Nepeta cataria L. throughout a Growing Season.

Catnip (Nepeta cataria L.) plants produce a wide array of specialized metabolites with multiple applications for human health. The productivity of such metabolites, including nepetalactones, and natural insect repellents is influenced by the conditions under which the plants are cultivated. In this study, we assessed how field-grown catnip plants, transplanted after being propagated via either single-node stem cuttings or seeds, varied regarding their phytochemical composition throughout a growing season in two distinct environmental conditions (Pittstown and Upper Deerfield) in the state of New Jersey, United States. Iridoid terpenes were quantified in plant tissues via ultra-high-performance liquid chromatography with triple quadrupole mass spectrometry (UHPLC-QqQ-MS), and phenolic compounds (phenolic acids and flavonoids) were analyzed via UHPLC with diode-array detection (UHPLC-DAD). The highest contents of total nepetalactones in Pittstown were found at 6 weeks after transplanting (WAT) for both seedlings and cuttings (1305.4 and 1223.3 mg/100 g, respectively), while in Upper Deerfield, the highest contents for both propagules were at 11 WAT (1247.7 and 997.1 mg/100 g, respectively) for seed-propagated and stem cuttings). The highest concentration of nepetalactones was associated with floral-bud to partial-flowering stages. Because plants in Pittstown accumulated considerably more biomass than plants grown in Upper Deerfield, the difference in nepetalactone production per plant was striking, with peak productivity reaching only 598.9 mg per plant in Upper Deerfield and 1833.1 mg per plant in Pittstown. Phenolic acids accumulated in higher contents towards the end of the season in both locations, after a period of low precipitation, and flavone glycosides had similar accumulation patterns to nepetalactones. In both locations, rooted stem cuttings reached their maximum nepetalactone productivity, on average, four weeks later than seed-propagated plants, suggesting that seedlings have, overall, better agronomic performance.

The auxin efflux carrier PIN1a regulates vascular patterning in cereal roots.

Barley (Hordeum vulgare) is an important global cereal crop and a model in genetic studies. Despite advances in characterising barley genomic resources, few mutant studies have identified genes controlling root architecture and anatomy, which plays a critical role in capturing soil resources. Our phenotypic screening of a TILLING mutant collection identified line TM5992 exhibiting a short-root phenotype compared with wild-type (WT) Morex background. Outcrossing TM5992 with barley variety Proctor and subsequent SNP array-based bulk segregant analysis, fine mapped the mutation to a cM scale. Exome sequencing pinpointed a mutation in the candidate gene HvPIN1a, further confirming this by analysing independent mutant alleles. Detailed analysis of root growth and anatomy in Hvpin1a mutant alleles exhibited a slower growth rate, shorter apical meristem and striking vascular patterning defects compared to WT. Expression and mutant analyses of PIN1 members in the closely related cereal brachypodium (Brachypodium distachyon) revealed that BdPIN1a and BdPIN1b were redundantly expressed in root vascular tissues but only Bdpin1a mutant allele displayed root vascular defects similar to Hvpin1a. We conclude that barley PIN1 genes have sub-functionalised in cereals, compared to Arabidopsis (Arabidopsis thaliana), where PIN1a sequences control root vascular patterning.

Ecological aspects and relationships of the emblematic Vachellia spp. exposed to anthropic pressures and parasitism in natural hyper-arid ecosystems: ethnobotanical elements, morphology, and biological nitrogen fixation

Main conclusionEmblematic Vachellia spp. naturally exposed to hyper-arid conditions, intensive grazing, and parasitism maintain a high nitrogen content and functional mutualistic nitrogen-fixing symbioses.AlUla region in Saudi Arabia has a rich history regarding mankind, local wildlife, and fertility islands suitable for leguminous species, such as the emblematic Vachellia spp. desert trees. In this region, we investigated the characteristics of desert legumes in two nature reserves (Sharaan and Madakhil), at one archaeological site (Hegra), and in open public domains at Al. Ward and Jabal Abu Oud. Biological nitrogen fixation (BNF), isotopes, and N and C contents were investigated through multiple lenses, including parasitism, plant tissues, species identification, plant maturity, health status, and plant growth. The average BNF rates of 19 Vachellia gerrardii and 21 Vachellia tortilis trees were respectively 39 and 67%, with low signs of inner N content fluctuations (2.10–2.63% N) compared to other co-occurring plants. The BNF of 23 R. raetam was just as high, with an average of 65% and steady inner N contents of 2.25 ± 0.30%. Regarding parasitism, infected Vachellia trees were unfazed compared to uninfected trees, thereby challenging the commonly accepted detrimental role of parasites. Overall, these results suggest that Vachellia trees and R. raetam shrubs exploit BNF in hyper-arid environments to maintain a high N content when exposed to parasitism and grazing. These findings underline the pivotal role of plant-bacteria mutualistic symbioses in desert environments. All ecological traits and relationships mentioned are further arguments in favor of these legumes serving as keystone species for ecological restoration and agro-silvo-pastoralism in the AlUla region.Graphical abstract

Gelatin/heparin coated bio-inspired polyurethane composite fibers to construct small-caliber artificial blood vessel grafts

Long-term patency and ability for revascularization remain challenges for small-caliber blood vessel grafts to treat cardiovascular diseases clinically. Here, a gelatin/heparin coated bio-inspired polyurethane composite fibers-based artificial blood vessel with continuous release of NO and biopeptides to regulate vascular tissue repair and maintain long-term patency is fabricated. A biodegradable polyurethane elastomer that can catalyze S-nitrosothiols in the blood to release NO is synthesized (NPU). Then, the NPU core-shell structured nanofiber grafts with requisite mechanical properties and biopeptide release for inflammation manipulation are fabricated by electrospinning and lyophilization. Finally, the surface of tubular NPU nanofiber grafts is coated with heparin/gelatin and crosslinked with glutaraldehyde to obtain small-caliber artificial blood vessels (ABVs) with the ability of vascular revascularization. We demonstrate that artificial blood vessel grafts promote the growth of endothelial cells but inhibit the growth of smooth muscle cells by the continuous release of NO; vascular grafts can regulate inflammatory balance for vascular tissue remodel without excessive collagen deposition through the release of biological peptides. Vascular grafts prevent thrombus and vascular stenosis to obtain long-term patency. Hence, our work paves a new way to develop small-caliber artificial blood vessel grafts that can maintain long-term patency in vivo and remodel vascular tissue successfully.

Biological and physiological effects in Bemisia tabaci feeding on tomatoes endophytically colonized by Beauveria bassiana.

Entomopathogenic fungi (EPF) treatment of plants may affect the survival and feeding preferences of herbivorous pests. However, comprehensive studies on the fitness across their entire life cycle, feeding behavior, and physiological changes in herbivores consuming EPF-treated plants within the tripartite interactions of EPF, plants, and pests are still limited. In this study, we utilized life tables, electrical penetration graph (EPG), and metabolomics to uncover the biological and physiological characteristics of Bemisia tabaci on tomato plants inoculated with Beauveria bassiana through root irrigation. Our study indicated that Beauveria bassiana Bb252 can penetrate the entire tissue from the point of inoculation, primarily colonizing the intercellular spaces and vascular tissue. However, this colonization is temporary, lasting no more than 35 days. Moreover, the population fitness and feeding behavior of Bemisia tabaci on tomato plants treated with Beauveria bassiana via root irrigation were significantly affected, showing a substantial 41.4% decrease in net reproductive rate (R0), a notable reduction in watery salivation, and shortened phloem ingestion. Lastly, we observed a significant decrease in hormones and amino acids of whiteflies that fed on Beauveria bassiana-treated tomato plants by root irrigation. Our results indicated that the endophyte, Beauveria bassiana Bb252, reduced demographic fitness of Bemisia tabaci by altering its hormones and amino acids levels. These findings enhance our understanding of multitrophic interactions in integrated pest management. © 2024 Society of Chemical Industry.

Tissue and cellular localization of condensed tannins in poplar roots and potential association with nitrogen uptake.

Condensed tannins are common in vegetative tissues of woody plants, including in roots. In hybrid poplar (Populus tremula x alba; also known as P. x canescens) CT assays indicated they were most concentrated in younger white roots and at the root tip. Furthermore, CT-specific staining of embedded tissue sections demonstrated accumulation in root cap cells and adjacent epidermal cells, as well as a more sporadic presence in cortex cells. In older, brown roots as well as roots with secondary growth (cork zone), CT concentration was significantly lower. The insoluble fraction of CTs was greatest in the cork zone. To determine if CT accumulation correlates with nutrient uptake in poplar roots, a microelectrode ion flux measurement (MIFE™) system was used to measure flux along the root axis. Greatest NH4 + uptake was measured near the root tip, but NO3- and Ca2+ did not vary along the root length. In agreement with earlier work, providing poplars with ample nitrogen led to higher accumulation of CTs across root zones. To test the functional importance of CTs in roots directly, CT-modified transgenic plants could be important tools.

Effect of biosynthesised silver nanoparticles as sterilant on physiological and biochemical characteristics in micropropagation of Musa sapientum L.

Green synthesis of silver nanoparticles (AgNPs) using fruit peel extract has gained considerable interest, as it is an eco-friendly and cost-effective method. However, studies on the use of biosynthesised AgNPs to sterilise plant tissue culture medium as an alternative to autoclaving are limited. Thus, this study presented a biogenic method for synthesising AgNPs using mangosteen peel extract. The biosynthesised AgNPs were characterised by different spectroscopic and microscopic methods, including UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive x-ray spectroscopy. The results showed that the phytochemical constituents in the mangosteen peel extract (MPE) helped to reduce Ag+ from AgNO3 to metallic silver (Ag0) and stabilise the particles. The formation of biogenic AgNPs was monitored by UV-vis demonstrating a characteristic peak at 425 nm. The AgNPs were spherical and crystalline. The size distribution of the biogenic AgNPs was 5–47 nm with an average diameter of 23.1 ± 6.8 nm. To evaluate the potential of the AgNPs for use as an alternative method to sterilise the culture medium, the antimicrobial activity of the biosynthesised AgNPs (0.1, 1, 10, 100, and 1000 mg l−1) was tested in the banana culture medium. The most feasible concentration of AgNPs to decontaminate the culture medium was 100 mg l−1. Moreover, the results demonstrated that adding 100 mg l−1 AgNPs to the culture medium promoted the growth of the plantlets without any toxic effects. Thus, biogenic AgNPs are a potential biocide to sterilise in vitro banana culture medium.

Floriculture and Transgenic

“Genetic engineering has revolutionized floriculture by enabling the modification of plant species and the creation of new flower color varieties (Chandler, Stephen et al, 2010). Despite the global cultivation of transgenic crops, floriculture has been slow to adopt transgenic breeding. "Floriculture, with its cut flower market as a significant component, is on track to achieve a market size of $43.8 billion by 2027, according to Markets and Markets. This industry plays a crucial role in uplifting rural economies through international trade. For instance, floriculture products from Africa find their way to markets in the U.S. and Europe. Similarly, Asian nations such as Japan, China, and India are strengthening their financial positions through the import and export of floriculture commodities (Tanaka, Yoshizu et al., 2009). One of the notable advancements in floriculture has been the creation of new flower color varieties by manipulating pigment metabolic pathways in plants. However, there are challenges. Some flowering plants, despite their high market value, do not realize their full economic potential due to issues like prolonged flowering seasons and diseases." These challenges can be addressed through the production of transgenic plants using genetic engineering and plant tissue culture techniques. The study aims to explore the potential of genetic engineering associated with plant tissue culture techniques in enhancing floriculture, particularly in developing new flower color varieties and improving the production of high-value flowering plants, thereby highlighting the economic impact of floriculture globally.

Community coalescence and plant host filtering determine the spread of tetracycline resistance genes from pig manure into the microbiome continuum of the soil–plant system

The spread of livestock manure-borne antibiotic resistance genes (ARGs) into agroecosystems through manure application poses a potential threat to human health. However, there is still a knowledge gap concerning ARG dissemination in coalescing manure, soil and plant microbiomes. Here, we examined the fate of tetracycline resistance genes (TRGs) originating from pig manure microbiomes and spread in the soil-A thaliana system and explored the effects of microbial functions on TRGs spread at different interfaces. Our results indicate that the TRGs abundances in all microbiome continuum of the soil-A. thaliana system were significantly increased with the application of a living manure microbiome, although the addition of manure with both an active and inactive microbiome caused a shift in the microbial community composition. This was attributed to the increasing relative abundances of tetA, tetL, tetM, tetO, tetW and tolC in the system. The application of living manure with DOX residues resulted in the highest relative abundance of total TRGs (3.30×10−3 copies/16S rRNA gene copies) in the rhizosphere soil samples. Community coalescence of the manure and soil microbiomes increased the abundance of Firmicutes in the soil and root microbiome, which directly explains the increase in TRG abundance observed in these interfaces. In contrast, the leaf microbiome differed markedly from that of the remaining samples, indicating strong plant host filtering effects on Firmicutes and TRGs from pig manure. The random forest machine learning model revealed microbial functions and their significant positive correlation with TRG abundance in the microbiome continuum of the system. Our findings revealed that community coalescence is the main driver of TRG spread from manure to the soil and root microbiomes. Plant host filtering effects play a crucial role in allowing certain microbial groups to occupy ecological niches in the leaves, thereby limiting the establishment of manure-borne TRGs in aboveground plant tissues.

Mercury Bioconcentration and Translocation in Rooted Macrophytes (Paspalum repens Berg.) from Floodplain Lakes in the Araguaia River Watershed, Brazilian Savanna

Macrophytes are fundamental photosynthetic organisms for functioning freshwater ecosystems, identified as potential bioindicators of mercury (Hg) in the environment. We quantified the concentrations of total Hg (THg) in water and macrophytes (Paspalum repens Berg.) from 17 lakes on the Araguaia River floodplain, aiming to compare the bioconcentration factor (BCF) in the aerial tissues and roots; evaluate the translocation factor (TF) between plant tissues; and assess the influence of environmental factors and land use on THg concentrations in water and macrophytes. The BCF was significantly higher in roots (1.29 ± 0.32) than in aerial tissues (0.41 ± 0.34), with low TF between plant tissues (0.14 ± 0.06). The highest concentrations of THg in water were determined in lakes with higher land use intensity and a pH close to neutral, indicating the transport of particulate-bound Hg and the immobilization in the water column. In contrast, wetlands were priority areas for the bioconcentration of THg in macrophytes, associated with sulfate, dissolved oxygen, and oxidation–reduction potential in the water. Thus, although P. repens is not a suitable bioindicator of Hg mobilization by anthropogenic land use in our study area, our results suggest the potential of macrophytes as bioindicators of sites that are favorable to Hg methylation.